Bone defect portions generated by bruise or illness are now treated by implanting patients' autogenous bones, similar bones provided by others, artificial bones made of metals such as titanium or hydroxyapatite ceramics, etc. Hydroxyapatite ceramics having bone conduction not achieved by conventional metals, polymers or alumina ceramics and directly bonding to bones have been gradually finding wider use as bone-repairing materials substituting autogenous bones in various fields such as oral surgery, neurological surgery, otorhinolaryngology, plastic surgery, etc., since their commercialization. However, artificial bones made of ceramics such as hydroxyapatite are hard and brittle, disadvantageous in difficulty in handling during operation. To solve such problems, apatite/collagen composites having sponge-like elasticity were developed for easy handling. However, filling bone defect portions having complicated shapes and different sizes is still difficult even with such materials, resulting in the likelihood of insufficient filling.
U.S. Pat. No. 5,776,193 discloses a porous, biodegradable, three-dimensionally fixed matrix for the replacement of bone comprising a bound network of water-insoluble, mineralized biopolymer (fixed phosphoric acid calcium) fibers, and a water-soluble binder (soluble collagen, etc.). However, this three-dimensionally fixed matrix fails to solve the above problems.